Search

The Advanced Ion Source for Hadrontherapy (AISHa) is an ECR ion source operating at 18 GHz, developed with the aim of producing high intensity and low emittance highly charged ion beams for hadrontherapy purposes. Due to its unique peculiarities, AISHa is a suitable choice for industrial and scientific applications. In the framework of the INSpIRIT and IRPT projects, in collaboration with Centro Nazionale di Adroterapia Oncologica (CNAO), new candidates for cancer treatment (including metal ion beams) are being developed. Moreover, within the IONS experiment, AISHa will be the test-bench for the development of an innovative active plasma chamber designed to increase plasma confinement by changing plasma fluxes. OES technique will be also used to refine techniques of non-invasive plasma diagnostics. Finally, a dedicated setup is under realization to provide impinging beams and detection systems for target production in nuclear physics experiments.

A new source for the TANDEM accelerator of LNS has been designed and installed. It is called NESTOR (Noble Elements Source for acceleraTORs) and consists of an ultra-compact ECR microwave discharge type ion source [1] operating around 6 GHz and up to 40 W of RF power, provided by a solid state power amplifier, coupled to a Li-Charge Exchange Cell (Li-CEC). It is engineered for the production of a wide range of 1+ and/or 1- ion beams from gaseous elements, in particular for noble gases. This work presents the characterization of the primary source and first operations of the whole setup on the HV platform (injector) of the Tandem. The He+ beams have been formerly characterized in terms of current, beam shape (by BaF2 beam viewers) and emittance (by the three-gradients method). Measurements have been carried out varying pressure, microwave frequency and RF power. Then, the source has been moved to the HV platform, coupled to the Li-CEC for first operations running in gas-exchange mode. Activities are ongoing to optimize beam transport towards the Tandem.

The Electron Cyclotron Resonance Ion Sources (ECRISs) development is strictly related to the availability of new diagnostic tools, as the existing ones are not adequate to such compact machines and to their plasma characteristics. Microwave interferometry is a non-invasive method for plasma diagnostics and represents the best candidate for plasma density measurement in hostile environment. Interferometry in ECRISs is a challenging task mainly due to their compact size. The typical density of ECR plasmas is in the range 10(11)-10(13) cm(-3) and it needs a probing beam wavelength of the order of few centimetres, comparable to the chamber radius. The paper describes the design of a microwave interferometer developed at the LNS-INFN laboratories based on the so-called "frequency sweep" method to filter out the multipath contribution in the detected signals. The measurement technique and the preliminary results (calibration) obtained during the experimental tests will be presented.

The EXCYT facility at the INFN-LNS is based on a K-800 superconducting cyclotron, as a driver for stable heavy ion beams (up to 80 MeV/amu, 1 pμA), and on a 15 MV tandem for post-accelerating the radioactive ion beams produced in a target-ion source (TIS) assembly. For some ion beam such as for Li, the higher extraction efficiency from the TIS is obtained by positive ionisation. Then the injection into the tandem is suitable only after a charge exchange (CEC) to obtain negative ions. The production of the radioactive ions were performed by injecting a 13C4+ primary beam of 45 MeV/amu on a graphite target up to a beam power of 150 W, while the ionisation was achieved by a tungsten positive surface ioniser. The Li+ has been produced at different energies to cross-check the transmission efficiency together with the charge exchange efficiency. The CEC consists of a cell containing Cs vapours which interact with the Li beam converting its charge from +1 to –1 by a two-step reaction; it was already characterized off-line and the results obtained at the EXCYT facility confirm our previous observations and expectations such as the efficiency at the extraction energies and the isotopic shift effect. Hereinafter the results of 8,9Li beams production are reported together with a brief presentation of the facility and with some future improvements and plan.

The characteristics of the ideal injector for high power proton accelerators have been studied in the last two years with the TRIPS ion source built at INFN-LNS, Catania and now installed at INFN-LNL, Legnaro. The beam production must obey to the request of high brightness, stability and reliability. The new Versatile Ion Source (VIS) is a permanent magnet version of the TRIPS source with a simpler extraction system and mechanics. Its design permits to operate at 80 kV without a bulky high voltage platform, in order to produce multi-mA beams of protons and H2+. The description of the source design and the expected performances will be presented.

At the Istituto Nazionale di Fisica Nucleare - Laboratori Nazionali del Sud (INFN-LNS) the beam commissioning of the high intensity Proton Source for the European Spallation Source (PS-ESS) started in November 2016. Beam stability at high current intensity is one of the most important parameter for the first steps of the ongoing commissioning. Promising results were obtained since the first source start with a 6 mm diameter extraction hole. The increase of the extraction hole to 8 mm allowed improving PS-ESS performances and obtaining the values required by the ESS accelerator. In this work, extracted beam current characteristics together with Doppler shift and emittance measurements are presented, as well as the description of the next phases before the installation at ESS in Lund.

ELIMED (Medical Applications at Extreme Light Infrastructure) is a task-force originally born by an idea of ELI-Beams (Prague, CZ)and INFN-LNS (Italian Institute for Nuclear Physics of Catania, I) researchers. It now involves other groups interested in the possibility to design and develop a new generation of hadrontherapy facilities using laser-accelerated ion beams. ELIMED main goal is to perform proof-of-principle experiments aimed to demonstrate that laser-accelerated high-energy proton beams (up to 70 MeV in the first phase) can be potentially used for the specific case of ocular proton therapy. For this purpose new devices for beam handling and transport will be developed as well as new methods for radiobiology and dosimetry. The involvement of INFN-LNS group takes advantage of the well-established expertise in dosimetry measurements and Monte Carlo calculations for medical physics, which has been achieved in several years of eye tumor treatments in the CATANA proton therapy facility. Recently, in the framework of an INFN activity, they have also designed, fabricated, calibrated and experimentally tested at PALS laser laboratory (Cz) a Thomson Parabola ion spectrometer with a wide acceptance and able to characterize laser-driven proton beams up to 20 MeV.

Intense heavy ion beam production with electron cyclotron resonance (ECR) ion sources is a common requirement for many of the accelerators under construction in Europe and elsewhere. An average increase of about one order of magnitude per decade in the performance of ECR ion sources was obtained up to now since the time of pioneering experiment of R. Geller at CEA, Grenoble, and this trend is not deemed to get the saturation at least in the next decade, according to the increased availability of powerful magnets and microwave generators. Electron density above 1013 cm(-3) and very high current of multiply charged ions are expected with the use of 28 GHz microwave heating and of an adequate plasma trap, with a B-minimum shape, according to the high B mode concept [S. Gammino and G. Ciavola, Plasma Sources Sci. Technol. 5, 19 (1996)]. The MS-ECRIS ion source has been designed following this concept and its construction is underway at GSI, Darmstadt. The project is the result of the cooperation of nine European institutions with the partial funding of EU through the sixth Framework Programme. The contribution of different institutions has permitted to build in 2006-2007 each component at high level of expertise. The description of the major components will be given in the following with a view on the planning of the assembly and commissioning phase to be carried out in fall 2007. An outline of the experiments to be done with the MS-ECRIS source in the next two years will be presented. (C) 2008 American Institute of Physics.

After the first operation of the SERSE superconducting source assembled with reduced performance coils, the tests of the new SERSE magnetic system were carried out with excellent results. The specifications of the design field were reached and exceeded. The new coils were mounted and SERSE is now able to run at full performance magnetic field. The today’s status of the facility, electron cyclotron resonance source and new magnetic configuration, is described. The first tests as a multicharged ion source have just started, and a few preliminary results are given and commented.

An oven for the feed of vapors from solid materials in the Superconducting Electron cyclotron Resonance ion SourcE (SERSE) has been designed, built and tested at the Laboratorio Nazionale del Sud. It is based on an electrically heated tungsten filament. In order to have a correct temperature distribution in the whole system and to lower the heating power, a finite elements code has been used for the design of busses and thermal shielding. A crucible temperature of 2000 °C has been measured by a pyrometer and a W/Re thermocouple. The tungsten filament as well as the other components have shown no significant damage, confirming the robustness and reliability of the system. Satisfactory Ni evaporation rates have been measured.

Over the past two years, INFN-LNS has undertaken to improve the source reliability for high-power proton accelerators. A full set of magnetic field measurements has been carried out to define a different design of the TRIPS magnetic system, based on permanent magnets, in order to increase the reliability of the source devoted to the ADS. The OPERA-3D package was used to design the new magnetic system as a combination of three rings of NdFeB magnets and soft iron in between. The description of the magnetic measurements and the comparison with the simulations are presented, along with the design of a new version of the source, called PM-TRIPS. Finally the new low-energy beam transfer line (LEBT) will be described, with particular regard to the improvement of accelerator availability, which can be obtained with the installation of two PM-TRIPS sources or more on a switching magnet.

During the last years big effort was devoted to increase the electrostatic deflectors’ reliability; this provided a better comprehension of the most significant effects concerning their working conditions. Deflectors were checked during the normal operation of the K800 Superconducting Cyclotron (CS) at LNS, at the operating pressure of 1 10-6mbar and a magnetic field of 3.5 T, the maximum cathodes voltage was – 60kV (120 kV/cm). The maximum extracted beam power was, up to now, 100 W; it is foreseen to extract up to 500 W. In this contribution we present the study, the tests and the design of a new water cooled electrostatic deflector. Particular effort was applied to optimise the beam extraction efficiency, the thermal dissipation, and the mechanical stability. In particularly we implemented new insulators, new anodised aluminium cathodes, new Ta septum, new voltage and water feedthroughs and a more efficient cooling system. All these improvements were performed to increase the mean time between failure and the beam current stability.

The intense proton source TRIPS, designed for the TRASCO project and now under installation at the Laboratori Nazionali di Legnaro, has been operational for 4 years at INFN-LNS and now all the macroscopic parameters are well defined, as for beam current, beam emittance, neutralization factor and reliability. No information has been available up to now about the plasma parameters for such a type of microwave discharge ion source, except for theoretical estimations. This report will describe the measurements of electron and ion density, temperature, plasma potential for typical operational conditions, along with the description of the experimental set-up used for the measurements, based on a Langmuir Probe

The major infrastructures of nuclear physics in Europe adopted the technology of electron cyclotron resonance (ECR) ion sources for the production of heavy-ion beams. Most of them use 14 GHz electron cyclotron resonance ion sources (ECRISs), except at INFN-LNS, where an 18 GHz superconducting ECRIS is in operation. In the past five years it was demonstrated, in the frame of the EU-FP5 RTD project called "Innovative ECRIS," that further enhancement of the performances requires a higher frequency (28 GHz and above) and a higher magnetic field (above 2.2 T) for the hexapolar field. Within the EU-FP6 a joint research activity named ISIBHI has been established to build by 2008 two different ion sources, the A-PHOENIX source at LPSC Grenoble, reported in another contribution, and the multipurpose superconducting ECRIS (MS-ECRIS), based on fully superconducting magnets, able to operate in High B mode at a frequency of 28 GHz or higher. Such a development represents a significant step compared to existing devices, and an increase of typically a factor of 10 for the intensity is expected (e.g., 1 emA for medium charge states of heavy ions, or hundreds of e mu A of fully stripped light ions, or even 1 e mu A of charge states above 50(+) for the heaviest species). The challenging issue is the very high level of magnetic field, never achieved by a minimum B trap magnet system; the maximum magnetic field of MS-ECRIS will be higher than 4 or 5 T for the axial field and close to 2.7 T for the hexapolar field. The detailed description of the MS-ECRIS project and of its major constraints will be given along with the general issues of the developments under way. (c) 2006 American Institute of Physics.

The EXCYT facility (EXotics with CYclotron and Tandem) at the INFN‐LNS is based on a K‐800 Superconducting Cyclotron injecting stable heavy‐ion beams (up to 80 MeV/amu, 1 eμA) into a target‐ion source assembly to produce the required nuclear species, and on a 15 MV Tandem for post‐accelerating the radioactive beams. Since December 1999 the Superconducting Cyclotron operates in a stand‐alone mode by means of the new axial injection beam line. The primary beam line has been already mounted and tested. The part of mass separator on the two high‐voltage platforms together with low intensity diagnostics is already installed while the ancillary items along with the part of mass separator at ground potential will be installed during the next stop of accelerator operations. The target‐ion source unit has been successfully tested on‐line at GANIL. The goal of such efforts will be represented by the test of the mass separator with stable beams planned at LNS by the end of the year. The commissioning of the EXCYT fa...

The Electrostatic Beam Deflectors for the K800 Superconducting Cyclotron are the most critical elements of the beam extraction system. It has been carried out an accurate investigation from the microscopic point of view, leading to a better comprehension of the complex phenomena taking part in the breakdown process. The environmental conditions are high electric field (up to 130 kV/cm), high magnetic field (up to 5 T) in addition with high energy (70 MeV/u) and high power ion beam. It has been found that all the materials constituent the electrostatic deflector, and not only the electrodes, give an important contribute to the mechanism of breakdown that occurs in two main ways: insulator metalization and enhanced electrodes electron emission. These two effects are involved in a positive feedback process which amplifies the effects leading to a fast breakdown. These phenomena are here shown and some possible solutions are at the moment under test using several bulk (Mo, Ti, Cu) and coating materials (TiN, Diamond Like Carbon).

The TRASCO intense proton source (TRIPS) has been installed at INFN-LNS in May 2000 and is now operational. The paper describes the design of the source along with the first results obtained and the next developments. The source has been able to deliver more than 20 mA of protons from a 5 mm hole at 65 kV extraction voltage, largely above the minimum requested current density. The optimisation of the source is under way, with special care to the reliability and satisfactory results have been achieved.